The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 12, 1988
Filed:
Apr. 28, 1987
Takeo Sato, Kawasaki, JP;
Nobuhiro Araki, Yokohama, JP;
Koichi Kawata, Tokyo, JP;
Noboru Nomura, Kyoto, JP;
Atsushi Ueno, Osaka, JP;
Shotaro Yoshida, Sendai, JP;
Matsushita Electrical Industrial Co., Ltd., Osaka, JP;
Abstract
A projection optical system for photolithography includes a refraction sub-system and a cata-dioptric sub-system optically connected to each other. The refraction sub-system extends at an object side. The cata-dioptric sub-system extends at an image side. The refraction sub-system is generally composed of refracting members. The cata-dioptric sub-system is generally composed of a phase compensating member, a concave mirror, and a convex mirror. The phase compensating member adjoins the refraction sub-system. At least the concave mirror has a central opening through which light passes. The light forms an image at a rear of the concave mirror.